JP5791682B2 - Cooker - Google Patents

Description

  The present invention relates to a cooking device equipped with an infrared sensor.

  In the conventional cooking device, as a method of detecting the temperature of the object to be heated (pan) placed on the top plate, a thermistor method for detecting the temperature transmitted from the pan through the top plate, and from the pan There is an infrared sensor system that detects radiated infrared radiation energy through a top plate.

  In the thermistor method, the thermistor is brought into close contact with the lower surface of a top plate made of crystallized glass having heat resistance and a low coefficient of thermal expansion. And the temperature of a pan is detected through a top plate by detecting the heat transmitted from the pan to the top plate. For this reason, when there is a gap between the top plate and the pan bottom, such as when the pan is warped, there is a problem that the accuracy of temperature measurement is significantly reduced. Further, since the heat of the pan is transmitted to the thermistor through the top plate, there is a problem that the followability of the detected temperature is poor.

  In the infrared sensor system, an infrared sensor is disposed below the top plate. And the infrared radiation energy (infrared ray amount) radiated from the pan placed on the top plate and transmitted through the top plate is detected by an infrared sensor, and the temperature of the pan is detected by the detected infrared ray amount. This infrared sensor method does not cause a temperature follow-up problem between the pan and the infrared sensor unlike the thermistor method. However, infrared rays are generated not only from the pan but also from the heated top plate. When the infrared sensor receives infrared rays from other than such a pan, there is a problem that accuracy of temperature measurement is lowered.

  Therefore, in the heating cooker described in Patent Document 1, a window material (glass material) having the same optical characteristics as that of the top plate made of glass is placed on the light receiving front of the infrared sensor, and the infrared light transmitted through the top plate is Without shielding, the infrared rays radiated from the lower surface of the top plate are shielded. Thereby, the detection ratio of the infrared rays radiated from the pan on the top plate is increased to improve the accuracy of temperature measurement.

  In addition, in the heating cooker described in Patent Document 2, a window material made of sapphire or the like is embedded in a through hole formed in the top plate above the infrared sensor, and infrared rays transmitted through the window material are detected. The accuracy of temperature measurement is improved.

JP 2010-244998 A (Claim 1) Japanese Patent Laying-Open No. 2004-95315 (Claim 1)

When measuring the infrared radiation energy, the heating cooker described in Patent Document 1 is a glass material (hereinafter, referred to as a glass material having transmission characteristics equivalent to that of the top plate). Glass filter).
However, when the said glass filter is used, while shielding the infrared rays (for example, wavelength 4.5micrometer or more) which a top plate radiates | emits, the shielded infrared rays are absorbed. Due to such absorption characteristics, the temperature of the glass filter itself is increased by the absorbed infrared rays, and infrared rays are emitted from the glass filter. And the infrared rays radiated | emitted from the glass filter inject into an infrared sensor. For this reason, there has been a problem that the accuracy of temperature measurement is lowered.

  In order to solve this problem, a method of detecting the temperature of the glass filter and offsetting the amount of infrared rays according to the temperature can be considered. However, in order to measure the temperature of the glass filter, it is necessary to separately provide a temperature detecting means, and there is a problem that an installation space is required and a manufacturing cost is improved.

  Moreover, since the heating cooker of patent document 2 embeds a window material in the through-hole of a top plate, the sealing property is ensured so that the food or juice spilled on the top plate may not enter the inside of the housing. There is a need. In addition, if a through hole is formed in the top plate, the strength of the top plate is reduced, so that reinforcement is required. For this reason, there existed a problem that manufacturing cost improved.

  The present invention has been made to solve the above-described problems, and can improve the detection accuracy of infrared rays emitted from an object to be heated placed on a top plate and improve the accuracy of temperature measurement. It is to obtain a heating cooker that can be.

The heating cooker according to the present invention includes a top plate on which a transmission part that transmits at least infrared rays in the first wavelength band is formed, and an object to be heated that is provided below the top plate and placed on the top plate. Heating means for heating the infrared ray sensor, an infrared sensor that is provided below the transmission part and has a condensing lens that collects the infrared rays, and detects the amount of infrared rays emitted from the object to be heated, and the transmission part An optical filter that is provided between the infrared sensor and transmits the infrared rays, an infrared temperature detection unit that detects a temperature of the object to be heated from a detection value of the infrared sensor, and a detection result of the infrared temperature detection unit And a control unit that controls the heating means, and the condenser lens is formed of a silicon base material , and has a wavelength at which light transmittance in the first wavelength band is greater than that in the first wavelength band. Than the transmittance of the belt There has a band-pass filter, the band-pass filter is constituted by a thin film of SiO, SiO2, MgF2, ZnS, and single layer at least one material is formed by depositing on the silicon substrate out of Ge, The optical filter is formed of a silicon substrate, and has a light transmittance in the first wavelength band higher than a transmittance in a wavelength band larger than the first wavelength band.

  In the present invention, an optical filter formed of a silicon substrate is provided between the transmission part of the top plate and the infrared sensor. For this reason, absorption of infrared rays by the optical filter can be suppressed, and emission of infrared rays from the optical filter can be suppressed. Therefore, it is possible to improve the detection accuracy of infrared rays emitted from the object to be heated placed on the top plate, and to improve the accuracy of temperature measurement.

It is a schematic top view of the heating cooker in Embodiment 1 of this invention. It is a schematic sectional drawing of the heating cooker in Embodiment 1 of this invention. It is a figure which shows the permeation | transmission characteristic of the top plate of the heating cooker in Embodiment 1 of this invention, and the spectral radiance of each temperature. It is an expanded sectional view of the principal part of the heating cooker in Embodiment 1 of this invention. It is sectional drawing of the infrared sensor of the heating cooker in Embodiment 1 of this invention. It is a figure which shows the permeation | transmission characteristic of the band pass filter of the heating cooker in Embodiment 1 of this invention. It is a figure which shows the permeation | transmission characteristic of the optical filter of the heating cooker in Embodiment 1 of this invention. It is a schematic sectional drawing of the heating cooker in Embodiment 2 of this invention. It is an expanded sectional view of the principal part of the heating cooker in Embodiment 2 of this invention. It is an expanded sectional view of the principal part of the heating cooker in Embodiment 2 of this invention. It is an expanded sectional view of the principal part of the heating cooker in Embodiment 3 of this invention. It is an expanded sectional view of the principal part of the heating cooker in Embodiment 4 of this invention.

  Hereinafter, an embodiment in which the cooking device of the present invention is applied to an IH cooking heater will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
1 is a schematic top view of a heating cooker according to Embodiment 1 of the present invention.
As shown in FIG. 1, the heating cooker includes a main body 1 and a top plate 2 that is provided on the main body 1 and on which an object to be heated (for example, a pan 100 or the like) is placed.

  The top plate 2 is made of crystallized glass having high heat resistance. The thickness of the top plate 2 is about 4 mm, for example. The top plate 2 transmits light of a predetermined wavelength band. A circular pan position display (heating ports 6a to 6c) indicating a rough placement position of the pan 100 corresponding to a heating range of the heating coil 14 to be described later is applied to the top plate 2 by coating or printing of paint. Is formed.

On the top surface of the top plate 2, a top surface coating 2 a is applied by coating or printing or the like for preventing the skidding of the pan 100 and protecting the surface of the top plate 2.
A lower surface coating 2b is applied to the lower surface of the top plate 2 by applying paint or printing. The lower surface coating 2b is for applying a coating that does not transmit visible light so as to hide the internal structure in order to hide the components in the main body 1 and improve the design. The lower surface coating 2b uses a silicon (Si) -based or ceramic-based paint having high heat resistance to protect the top plate 2 from heat.

  In addition, a transmission window 20 that transmits infrared rays is formed in the heating ports 6 a and 6 b of the top plate 2. The transmission window 20 is formed at a position above the infrared sensor 5 described later. The transmission window 20 is configured by a portion where the upper surface coating 2a and the lower surface coating 2b are not applied, or a portion where coating or printing is performed to such an extent that infrared rays can be transmitted. Thereby, the transmissive window 20 reduces the attenuation of the infrared radiation energy radiated from the pan 100. In addition, when coating the transmission window 20, it is desirable to use an infrared wavelength transmission paint that transmits a wavelength band with high transmittance of crystallized glass.

  On the front surface side of the top plate 2, upper surface operation units 3a to 3b corresponding to the respective heating coils 14 of the heating ports 6a to 6c are provided. The upper surface operation units 3a to 3b input operations related to cooking by operation from the user, such as setting of the energization state of the heating coil 14 (heating power setting). The upper surface operation units 3a to 3b function as menu setting means for setting “preheating”, “fried food”, “boiled”, etc. of automatic cooking, and input an operation for selecting a menu to be used.

On the front side of the top plate 2, upper surface display portions 4a to 4c corresponding to the respective heating coils 14 of the heating ports 6a to 6c are provided. The upper surface display units 4a to 4c are provided, for example, in the vicinity of the upper surface operation units 3a to 3c. The upper surface display units 4a to 4c display the energization state of the heating coils 14 of the heating ports 6a to 6c and the contents of input operations from the upper surface operation units 3a to 3c.
Further, the upper surface display units 4a to 4c display the heating power input from the upper surface operation units 3a to 3b, the cooking menu input by the menu setting unit, and the like. In the cooking preheating menu set by the menu setting means, the upper surface display units 4a to 4c are configured to “preheat” so that the user can be informed of the timing of adding ingredients when the pan 100 is preheated and the temperature reaches an appropriate temperature. “Middle”, “Warming”, etc. can be displayed.

  In addition, at the rear of the upper surface of the main body 1, intake ports 9 a and 9 b that communicate with the inside of the main body 1 and take in the cooling air into the main body 1, and an exhaust port 8 that discharges the cooling air taken into the main body 1. And are provided. The cooling air sucked into the main body 1 incorporates a control board incorporating an electronic circuit constituting the control unit 17 and the like provided in a substrate case in the main body 1 and a high-frequency inverter 18 energizing the heating coil 14. Cool the inverter board. Then, it blows off from the cooling port provided in the upper surface of the substrate case, and the heating coil 14 is cooled. The cooling air after cooling the inside of the main body 1 is discharged from the exhaust port 8.

  A grill heating means (not shown) for grilling fish and pizza is provided on the front surface of the main body 1. The grill heating means has a box shape with an open front, and a heating element such as a sheathed heater and a thermistor (not shown) for detecting the internal temperature are provided in the internal cooking cabinet. Cook cooked ingredients such as fish or pizza.

FIG. 2 is a schematic cross-sectional view of the heating cooker according to Embodiment 1 of the present invention. Note that FIG. 2 shows the configuration of one heating port (for example, the heating port 6a).
As shown in FIG. 2, heating coils 14 are respectively disposed below the top plate 2. The heating coil 14 induction-heats an object to be heated (for example, the pan 100) placed on the top plate 2.
The heating coil 14 is installed on the heating coil support means 19. Further, between the heating coil support means 19 and the top plate 2, a cushioning material 19b (see FIG. 3) attached to the outer peripheral edge of the heating coil support means 19 is provided. The heating coil support means 19 keeps the gap between the lower surface of the top plate 2 and the heating coil 14 constant.

The heating coil 14 includes an annular inner coil 14a and an annular outer coil 14b arranged with an annular gap provided outside thereof. The reason for providing a gap in the heating coil 14 is to make the temperature of the pan 100 uniform by dispersing the magnetic flux generated by the inner coil 14a and the outer coil 14b.
Further, since the heating coil 14 is configured by winding the inner coil 14a and the outer coil 14b in an annular shape, the heating distribution of the object to be heated has the same degree of heating on a concentric circle as viewed from the center of the heating coil 14. . The heating coil 14 may or may not be electrically connected to the inner coil 14a and the outer coil 14b.

The heating coil 14 employs litz wire to suppress the skin effect. The heating coil 14 is applied with a voltage of several hundred volts at a high frequency of several tens of kHz by the high frequency inverter 18, applies a high frequency magnetic field to the pan 100 to generate an eddy current in the pan 100, and makes the pan 100 itself self. Heat to exotherm.
In addition, although this Embodiment demonstrates the induction heating cooking appliance which supplies a high frequency current to the heating coil 14, and performs induction heating, this invention is not limited to this. For example, an electric heater (for example, a nichrome wire, a halogen heater, or a radiant heater) using a radiant heat source that is heated by radiation may be used as the heating means.

  The control unit 17 controls the high-frequency inverter 18 based on operation inputs from the upper surface operation units 3a to 3b and detection results of a top plate temperature detection unit 11 and an infrared temperature detection unit 13 described later.

  A contact temperature sensor 10 composed of a thermistor is provided on the lower surface of the top plate 2. The contact temperature sensor 10 is provided in close contact with the lower surface of the top plate 2. For example, the contact temperature sensor 10 is disposed in an annular gap between the inner coil 14a and the outer coil 14b in plan view. The contact-type temperature sensor 10 detects through the top plate 2 and outputs the detection result to the top plate temperature detecting means 11. The top plate temperature detecting means 11 detects the temperature of the pan 100 placed above the heating coil 14 based on the detection result of the contact temperature sensor 10.

An infrared sensor 5 (including an amplification circuit) that detects an infrared ray amount (radiation energy amount) emitted from the pan 100 is provided below the transmission window 20 of the top plate 2. The infrared sensor 5 is disposed below the heating coil 14 and is disposed in an annular gap between the inner coil 14a and the outer coil 14b in plan view.
As shown in FIG. 2, the viewing angle of the infrared sensor 5 is a range detected by temperature detection spots of φ10 to φ15 at the position of the lower surface of the top 2. This makes it difficult to receive infrared rays emitted from the heating coil 14, the heating coil support means 19, the lower surface coating 2 b provided outside the transmission window 20, and the like.
The infrared sensor 5 includes a sensor using a thermal detection element and an amplification circuit that amplifies a voltage signal output from the sensor. The infrared sensor 5 inputs the amplified voltage signal to the infrared temperature detection means 13. The infrared temperature detection means 13 detects the temperature of the pan 100 placed above the heating coil 14 based on the detection result of the infrared sensor 5.

The infrared sensor 5 is housed in the sensor case 21. The sensor case 21 is fixed to the heating coil support means 19 and positions the infrared sensor 5.
Furthermore, an optical filter 22 that transmits infrared rays of a predetermined wavelength band is provided between the transmission window 20 and the infrared sensor 5. Details will be described later.

The heating coil support means 19 corresponds to the “support means” in the present invention.
The transmission window 20 corresponds to a “transmission part” in the present invention.
The pan 100 corresponds to the “object to be heated” in the present invention.

(Transmission characteristics of top plate 2)
FIG. 3 is a diagram showing the transmission characteristics of the top plate of the cooking device and the spectral radiance at each temperature in the first embodiment of the present invention.
In FIG. 3, the dotted line indicates the infrared transmittance of the top plate 2 (crystallized glass), and the solid line indicates the spectral radiance at each temperature of the black body.
As shown by the dotted line in FIG. 3, it can be seen that the top plate 2 (crystallized glass) has a low infrared transmittance in a wavelength band exceeding about 4.5 μm.
Further, as shown by the solid line in FIG. 3, it can be seen that as the temperature of the object rises, the infrared wavelength that is the peak of the emitted infrared light becomes shorter and the amount of radiant energy increases. It can also be seen that the peak wavelength of the spectral radiance is a wavelength band exceeding about 4.5 μm at a high temperature assumed in cooking (for example, 250 ° C.).

For this reason, in the first embodiment, the optical filter 22 has a transmittance of light in a wavelength band that transmits the top plate 2 higher than a transmittance in a wavelength band that exceeds the wavelength band that transmits the top plate 2. High transmission characteristics. For example, the optical filter 22 has a transmission characteristic in which the transmittance of light of 3.0 μm or more and 4.5 μm or less is higher than the transmittance of a wavelength band exceeding 4.5 μm. From this, it is set as the structure which reduces the infrared rays radiated | emitted by the temperature rises, such as the top plate 2 and the heating coil 14. FIG.
The optical filter 22 is formed of a Si (silicon) base material. Since the Si base material has a refractive index as high as 3 or more in the infrared region and a high reflectance, infrared light other than the wavelength band that transmits is substantially reflected. Thereby, the temperature rise by infrared absorption can be suppressed, and the infrared radiation accompanying the temperature rise of optical filter 22 itself can be suppressed.

As described above, most of the infrared rays emitted from the top plate 2 itself are shielded by the optical filter 22, so that the infrared rays emitted from the pan 100 can be accurately detected by the infrared sensor 5.
In addition, the infrared rays emitted from the pan 100 placed on the top plate 2 can be accurately detected by the infrared sensor 5 without considering the heat absorption of the optical filter 22.
Moreover, the optical filter 22 can suppress the absorption of the infrared rays which the top plate 2 radiated | emitted by forming with Si base material, and can suppress the temperature rise of the optical filter 22. FIG. Therefore, it is not necessary to consider the secondary radiation effect from the optical filter 22, and highly accurate temperature detection is possible without providing additional temperature detection means.

Moreover, as shown in FIG. 3, the top plate 2 (crystallized glass) has a transmission characteristic having a high transmittance in the visible light wavelength band (about 0.38 to 0.83 μm). That is, when the upper surface coating 2a and the lower surface coating 2b are not applied to the transmission window 20 of the top plate 2, or when the coating is performed to such an extent that infrared rays can be transmitted, the transmission window 20 transmits visible light and is transparent. It will have. Thereby, when a user looks at the top plate 2 from directly above the transmission window 20 or from an oblique direction, the internal structure of the cooking device may be visually recognized, and the appearance may be impaired and the design may be deteriorated.
In the first embodiment, an optical filter 22 formed of a Si base material is provided between the transmission window 20 and the infrared sensor 5. Since the Si base material has high reflectivity, has a metallic luster, and reflects visible light, it is possible to prevent the internal structure from being seen beyond the optical filter 22.

  The wavelength band of 3.0 μm or more and 4.5 μm or less corresponds to the “first wavelength band” in the present invention.

(Infrared sensor 5 and optical filter 22)
Next, details of the infrared sensor 5 and the optical filter 22 will be described.

FIG. 4 is an enlarged cross-sectional view of a main part of the heating cooker according to Embodiment 1 of the present invention.
As shown in FIG. 4, the infrared sensor 5 is positioned and placed inside the sensor case 21. The sensor case 21 has an opening at a position corresponding to the visual field of the infrared sensor 5. The sensor case 21 is attached to a heating coil support means 19 that supports the heating coil 14 via a gap material 19a. Thereby, a gap is formed between the upper surface of the sensor case 21 and the heating coil support means 19. Cooling air that flows into the inside of the main body 1 from the intake ports 9a and 9b and cools the heating coil 14 passes through the gap.
Thus, the upper part of the sensor case 21 is not sealed and is open. For this reason, the temperature rise of the infrared sensor 5 can be suppressed and failure of the infrared sensor 5 can be prevented. Moreover, the raise of the ambient temperature of the infrared sensor 5 can be suppressed, and the fall of temperature detection accuracy can be suppressed. For example, when the sensor case 21 is formed of resin, this effect is more remarkable because the resin has a large heat capacity and low thermal conductivity.

  The infrared sensor 5 has a condenser lens 23 that collects infrared rays. The condenser lens 23 is provided with a band pass filter 24 in which thin films are deposited and laminated. Thus, by providing the band pass filter 24, the transmittance of the wavelength band exceeding the wavelength band that transmits the top plate 2 is lowered, and the infrared rays emitted by the temperature rise of the top plate 2, the heating coil 14, and the like are reduced. It is configured.

  The optical filter 22 is disposed in the gap between the inner coil 14 a and the outer coil 14 b of the heating coil support means 19. For example, the optical filter 22 is disposed at almost the same height as the installation surface of the inner coil 14 a and the outer coil 14 b of the heating coil support means 19. Thereby, the infrared rays radiated from the inner coil 14 a and the outer coil 14 b and entering the infrared sensor 5 can be blocked (reduced) by the optical filter 22.

FIG. 5 is a cross-sectional view of the infrared sensor of the heating cooker according to the first embodiment of the present invention.
In FIG. 5, the condenser lens 23 for limiting the viewing angle of infrared rays is provided with band pass filters 24 on both sides of the surface through which infrared rays are transmitted.
The bandpass filter 24 is configured by a thin film formed by evaporating at least one material of SiO, SiO 2, MgF 2, ZnS, and Ge on the condenser lens 23. The band-pass filter 24 may be formed of only one layer with a film thickness of several μm, or may be formed by stacking multiple layers.

  The band-pass filter 24 has a transmission characteristic in which the transmittance of light in the wavelength band that transmits the top plate 2 is higher than the transmittance in the wavelength band that exceeds the wavelength band that transmits the top plate 2. For example, the band pass filter 24 has a transmission characteristic in which the transmittance of light of 3.0 μm or more and 4.5 μm or less is higher than the transmittance of a wavelength band exceeding 4.5 μm.

  From this, it is set as the structure which reduces the infrared rays radiated | emitted by the temperature rises, such as the top plate 2 and the heating coil 14. FIG. In other words, the bandpass filter 24 is configured to heat the top plate 2 by heat conduction and radiation from the pan 100 and suppress the influence of infrared radiation energy radiated from the top plate 2, so that the infrared rays radiated from the bottom surface of the pan 100. The SN characteristic is improved by increasing the ratio of radiant energy.

  The condensing lens 23 is formed of a Si (silicon) base material. Since the Si base material has a refractive index as high as 3 or more in the infrared region and a high reflectance, infrared light other than the wavelength band that transmits is substantially reflected. Thereby, the temperature rise by infrared absorption can be suppressed, and the infrared radiation accompanying the temperature rise of the condensing lens 23 itself can be suppressed.

The thermopile chip 25 is configured by connecting a plurality of thermocouples each having a hot junction and a cold junction in series, and generates a thermoelectromotive force according to a temperature difference between the hot junction and the cold junction (Seebeck). effect). The thermoelectromotive force is amplified by an amplifier circuit (not shown), and the amplified voltage signal is input to the infrared temperature detecting means 13.
The infrared sensor self-temperature detecting means 26 measures the temperature around the thermopile chip 25 (cold junction temperature) and inputs the measurement result to the infrared temperature detecting means 13.
The infrared temperature detection means 13 detects the temperature of the pan 100 according to the temperature measured by the infrared sensor self-temperature detection means 26 and the thermoelectromotive force measured by the thermopile chip 25.

FIG. 6 is a diagram showing the transmission characteristics of the band-pass filter of the cooking device according to Embodiment 1 of the present invention.
As shown in FIG. 6, the band-pass filter 24 has a transmission characteristic in which the transmittance of light of 3.0 μm or more and 4.5 μm or less is higher than the transmittance of the wavelength band of more than 4.5 μm and 15 μm or less.
On the other hand, the transmittance remains at a wavelength of 12 μm or more. In order to reduce the remaining transmittance other than the desired wavelength band, for example, it is possible to lower the remaining transmittance by overlapping the film thickness of a specific material. However, if a multilayer film is formed on the condenser lens 23, the manufacturing cost becomes high.
Therefore, in the first embodiment, the optical filter 22 is provided to reduce the transmittance in the wavelength band exceeding 4.5 μm remaining in the band pass filter 24.

FIG. 7 is a diagram showing the transmission characteristics of the optical filter of the cooking device according to Embodiment 1 of the present invention.
The optical filter 22 is configured by a thin film formed by vapor-depositing at least one material of SiO, SiO2, MgF2, ZnS, and Ge on one or both surfaces of a surface through which infrared rays are transmitted.
As shown in FIG. 7, the optical filter 22 has a transmission characteristic in which the transmittance of light of 3.0 μm or more and 4.5 μm or less is higher than the transmittance in the wavelength band of more than 4.5 μm and 15 μm or less. For example, in the band-pass filter 24, the transmittance in the wavelength band of 12 μm to 15 μm where the transmittance remains is about 40%.

As described above, by providing the optical filter 22, it is possible to reduce the transmittance in the wavelength band exceeding 4.5 μm remaining in the band pass filter 24.
Therefore, the S / N ratio for comparing the ratio (S) of the infrared rays transmitted through the transmission window 20 of the top plate 2 and the infrared rays (N) radiated from the top plate 2 itself is improved and placed on the top plate 2. Infrared rays emitted from the pan 100 can be detected with high accuracy by the infrared sensor 5.
Further, by providing the optical filter 22, it is not necessary to configure the band pass filter 24 of the condenser lens 23 with a multilayer film, and the manufacturing cost can be reduced.

The optical filter 22 may be formed as a single-layer thin film made of any one material of SiO, SiO2, MgF2, ZnS, or Ge only on one surface through which infrared rays are transmitted.
Even in such a configuration, the optical filter 22 can reduce the transmittance in the wavelength band exceeding 4.5 μm, and infrared rays emitted from the pan 100 placed on the top plate 2 can be reduced by the infrared sensor 5. It can be detected with high accuracy. In addition, the manufacturing cost can be further reduced.

As described above, in the present embodiment, the optical filter 22 that transmits infrared light is provided between the transmission window 20 and the infrared sensor 5. The optical filter 22 is formed of a silicon base material.
For this reason, absorption of infrared rays by the optical filter 22 can be suppressed, and emission of infrared rays from the optical filter 22 can be suppressed. Therefore, the detection accuracy of infrared rays emitted from the pan 100 placed on the top plate 2 can be improved, and the accuracy of temperature measurement can be improved.
Further, it is not necessary to consider the secondary radiation effect from the optical filter 22, and it is possible to detect the temperature with high accuracy while reducing the manufacturing cost without additionally providing a temperature detecting means.

Embodiment 2. FIG.
FIG. 8 is a schematic cross-sectional view of the heating cooker according to the second embodiment of the present invention.
FIG. 9 is an enlarged cross-sectional view of a main part of the heating cooker according to Embodiment 2 of the present invention.
Hereinafter, the cooking device according to the second embodiment will be described focusing on the differences from the first embodiment. In addition, the same code | symbol is attached | subjected to the structure similar to the said Embodiment 1. FIG.

As shown in FIGS. 8 and 9, the heating cooker according to the second embodiment includes a light shielding means 30 between the heating coil support means 19 and the top plate 2.
The infrared sensor 5 is composed of a pair of plate-like members arranged to face each other across the field of view. The pair of plate members constituting the light shielding means 30 may be curved plate shapes. The light shielding means 30 may be configured by a cylindrical member arranged so as to surround the visual field of the infrared sensor 5.

  When the light shielding means 30 is constituted by a pair of plate-like members, cooling air can be passed between the plate-like members, and the temperature rise of the light shielding means 30 can be suppressed. Therefore, the infrared radiation accompanying the temperature rise of the light shielding means 30 can be suppressed, and the decrease in detection accuracy of the infrared sensor 5 can be suppressed.

  Note that a structure having a low emissivity paint or a nonmagnetic metal may be provided on the surface of the light shielding means 30 on the optical path 28 side of the infrared sensor 5. Thereby, the radiation | emission of the infrared rays accompanying the temperature rise of the light-shielding means 30 can be suppressed, and the fall of the detection accuracy of the infrared sensor 5 can be suppressed.

The light shielding means 30 has an upper end formed above the upper surface of the heating coil 14. In addition, you may provide so that the top plate 2 and the light-shielding means 30 may contact | connect through a buffer member.
The light shielding means 30 may be integrally formed with the heating coil support means 19. For example, the light shielding means 30 may be integrally formed by bending the inner coil 14a and the outer coil 14b of the heating coil support means 19 toward the top plate 2 direction.

  The optical filter 22 is attached to the upper end of the light shielding means 30. The infrared sensor 5 is disposed below the heating coil support means 19.

  As described in the first embodiment, when the top surface coating 2a and the bottom surface coating 2b are not applied to the transmission window 20 of the top plate 2, or when coating is performed to such an extent that infrared rays can be transmitted, the transmission window 20 is Visible light is transmitted and has transparency. Thereby, when the user views the top plate 2 from directly above or obliquely from the transmission window 20, depending on the size of the transmission window 20 and the installation of the heating coil support means 19, the heating coil 14 made of copper or the like, etc. The internal structure of the cooking device may be visually recognized, and the appearance may be impaired and the design may be deteriorated.

  In the second embodiment, the light shielding means 30 is provided between the heating coil support means 19 and the top plate 2, and the optical filter 22 is attached to the light shielding means 30 so that the inside of the heating coil 14 and the like from the transmission window 20. The structure can be prevented from being seen.

  The infrared sensor 5 is configured to receive infrared energy from the direction of the transmission window 20 by narrowing the viewing angle by the condensing lens 23, but several percent receives infrared energy emitted from the vicinity of the heating coil 14. In some cases. In this case, when energized, the heating coil 14 self-heats due to the coil resistance, and the infrared radiation energy accompanying this heat generation may affect the detection value of the infrared sensor 5.

  In the second embodiment, the light shielding means 30 is provided between the heating coil support means 19 and the top plate 2, and the optical filter 22 is attached to the light shielding means 30, so that the infrared rays traveling from the heating coil 14 to the infrared sensor 5 are provided. Can be shielded. Therefore, the detection accuracy of infrared rays emitted from the pan 100 placed on the top plate 2 can be further improved, and the accuracy of temperature measurement can be further improved.

  Further, by attaching the optical filter 22 to the upper end of the light shielding means 30, infrared rays having a wavelength band of 4.5 μm or more are shielded, so the surface of the light shielding means 30 on the optical path 28 side of the infrared sensor 5 absorbs heat. In addition, it is possible to suppress the influence of the temperature rise of the light shielding means 30.

  Similarly to the first embodiment, the infrared ray radiated from the pan 100 placed on the top 2 is provided with the band-pass filter 24 and the optical filter 22 provided in the infrared sensor 5. The S / N ratio for comparing (S) with the infrared ray (N) emitted from the top plate 2 itself is improved, and the infrared ray emitted from the pan 100 placed on the top plate 2 is accurately detected by the infrared sensor 5. can do.

(Installation structure of the optical filter 22)
As described above, the optical filter 22 is made of a Si base material. The optical filter 22 is manufactured by depositing a thin film in the state of a silicon wafer and dicing into a square, hexagon or octagon having a diameter of about 10 to 20 mm. Although a circular shape may be used, the above shape is preferable because the yield is poor and the cost is increased. As described above, the optical filter 22 made of the Si base is formed of a polygonal flat plate.
On the other hand, the light shielding means 30 has a notch corresponding to the shape of the optical filter 22. The optical filter 22 is fixed by fitting the optical filter 22 into the cutout of the light shielding means 30.
With such a configuration, when the optical filter 22 is installed on the light shielding means 30, it can be fitted in accordance with the corner so as not to be displaced, and the occurrence of variations during installation can be suppressed.

The optical filter 22 is bonded and fixed to the light shielding means 30 with an epoxy-based or silicon-based adhesive.
In order to receive the radiant heat from the top plate 2 which became high temperature, it is desirable to use the above-mentioned adhesive that can be used in a high temperature environment. In addition, the temperature of the top plate 2 may be 200 ° C. or higher when cooking “fried food” or “fried food”, for example.

The fixing of the optical filter 22 and the light shielding means 30 is not limited to adhesion.
For example, as shown in FIG. 10, the optical filter 22 is connected to the upper end of the light shielding unit 30 and the light shielding unit by a light shielding unit cap 31 that covers at least a part of the upper end of the light shielding unit 30 and the side surface opposite to the field of view of the light shielding unit 30. You may fix in the state pinched | interposed between the caps 31. FIG.
Specifically, the protrusion 32 is provided outside the optical path 28 of the infrared sensor 5 of the light shielding means 30. A concave fitting portion corresponding to the protruding portion 32 is formed on the side surface of the light shielding means cap 31, and an opening having a size exceeding 50% (half-value angle) of the visual field of the infrared sensor 5 is formed on the upper portion. Has been. When the optical filter 22 is placed on the upper end of the light shielding unit 30, the optical filter 22 is physically fixed when the light shielding unit 30 and the light shielding unit cap 31 are combined. In addition, the fitting part of the light-shielding means cap 31 should just be a shape fitted to the projection part 32, and may be opening. Alternatively, a groove may be formed instead of the projection 32 of the light shielding means 30 and a convex fitting part may be formed on the light shielding means cap 31.
The light shielding means cap 31 corresponds to a “pressing member” in the present invention.

  With such a configuration, the optical filter 22 can be fixed without using an adhesive, so that it is not necessary to consider deterioration of the adhesive due to radiant heat from the top plate 2.

Embodiment 3 FIG.
FIG. 11: is an expanded sectional view of the principal part of the heating cooker in Embodiment 3 of this invention.
Hereinafter, the cooking device according to the third embodiment will be described focusing on the differences from the second embodiment. In addition, the same code | symbol is attached | subjected to the structure similar to the said Embodiment 2. FIG.

As shown in FIG. 11, in the cooking device according to the third embodiment, the optical filter 22 is attached to the lower part of the light shielding means 30.
In the light shielding means 30, a groove corresponding to the thickness of the optical filter 22 is formed on the side surface of the optical path 28 of the infrared sensor 5 below the heating coil support means 19. The optical filter 22 is fixed by sliding the optical filter 22 into the groove of the light shielding means 30 and inserting it. In addition, the structure which attaches the optical filter 22 is not restricted to this, It can fix by arbitrary structures, such as fixing with the adhesive agent mentioned above.

  Thus, by attaching the optical filter 22 to the lower part of the light shielding means 30, when the light shielding means 30 is heated, the infrared light emitted from the light shielding means 30 itself is incident on the optical sensor 5 before entering the infrared sensor 5. 22 can be shielded (reduced). Therefore, the detection accuracy of infrared rays emitted from the pan 100 placed on the top plate 2 can be further improved, and the accuracy of temperature measurement can be further improved.

Embodiment 4 FIG.
FIG. 12 is an enlarged cross-sectional view of a main part of the heating cooker according to Embodiment 4 of the present invention.
Hereinafter, the cooking device according to the fourth embodiment will be described with a focus on differences from the third embodiment. In addition, the same code | symbol is attached | subjected to the structure similar to the said Embodiment 3. FIG.

As shown in FIG. 12, the heating cooker according to the fourth embodiment is provided with a magnetic shielding means 40 between the heating coil support means 19 and the sensor case 21.
The magnetic shield 40 is made of a nonmagnetic metal and shields the magnetic flux generated from the heating coil 14. The optical filter 22 is disposed in contact with the magnetic shielding means 40. For example, when the optical filter 22 is disposed at the lower end of the light shielding means 30 and the magnetic shielding means 40 is fixed to the heating coil support means 19, the optical filter 22 is shared. Tighten and fix.

As described in the first embodiment, the cooling air that flows into the inside of the main body 1 from the air inlets 9a and 9b and cools the heating coil 14 flows through the lower surface of the heating coil support means 19. For this reason, at least a part of the magnetic shielding means 40 is cooled by the cooling air. By cooling the magnetic-shielding means 40, the optical filter 22 in contact therewith is also cooled.
For this reason, the infrared radiation accompanying the temperature rise of the optical filter 22 can be suppressed. Therefore, the detection accuracy of infrared rays emitted from the pan 100 placed on the top plate 2 can be further improved, and the accuracy of temperature measurement can be further improved.

For example, the temperature of the magnetic shielding means 40 made of nonmagnetic metal such as aluminum (230 W · m ⁻¹ · K ⁻¹ ) or copper (400 W · m ⁻¹ · K ⁻¹ ) having high thermal conductivity is The temperature is lower than that of a resin material having a low rate (as an example, PPS: 0.3 W · m ⁻¹ · K ⁻¹ ). Therefore, it is possible to prevent the temperature rise by contacting the magnetically shielded means 40, an optical filter 22 consisting of Si substrates ^{(168W · m -1 · K -1} ).

In addition to the above configuration, at least one surface outside the sensor case 21 made of resin may be subjected to metal plating.
Thereby, the thermal conductivity of the surface of the sensor case 21 that has been subjected to metal plating can be improved, and the temperature increase of the magnetic shield means 40 in contact with the sensor case 21 and the optical filter 22 in contact with the magnetic shield means 40 is suppressed. can do.

  When the sensor case 21 is subjected to metal plating, the temperature rise of the optical filter 22 may be suppressed by bringing the sensor case 21 and the optical filter 22 into contact without providing the magnetic shielding means 40.

(Modification)
In the first to fourth embodiments, the case where the bandpass filter 24 in which a thin film is deposited on the condenser lens 23 of the infrared sensor 5 is provided and the single-layer thin film is formed on the optical filter 22 has been described. Is not limited to this.
A configuration in which a plurality of layers of the band pass filter 24 applied to the condenser lens 23 is changed to a single layer thin film applied to the optical filter 22 and a band pass filter 24 in which thin films are deposited on the optical filter 22 is provided. good. Thereby, productivity can be improved by vapor-depositing a single layer film on the condensing lens 23.

  Thus, even if the thin film formed on the optical filter 22 and the condensing lens 23 and the bandpass filter 24 are changed, it is possible to obtain an effect equivalent to the effect described above. In addition, the bandpass filter 24 is applied to the optical filter 22 which is a flat plate, and the single-layer filter is provided on the condensing lens 23 having a difficult management value, thereby facilitating manufacturing management and reducing the cost together with the yield improvement. Is possible.

  DESCRIPTION OF SYMBOLS 1 Main body, 2 Top plate, 2a Upper surface coating, 2b Lower surface coating, 3a-3c Upper surface operation part, 4a-4c Upper surface display part, 5 Infrared sensor, 6a-6c Heating port, 8 Exhaust port, 9a, 9b Inlet port, 10 Contact type temperature sensor, 11 Top plate temperature detection means, 13 Infrared temperature detection means, 14 Heating coil, 14a Inner coil, 14b Outer coil, 17 Control unit, 18 High frequency inverter, 19 Heating coil support means, 19a Gap material, 19b Buffer Material, 20 Transmission window, 21 Sensor case, 22 Optical filter, 23 Condensing lens, 24 Band pass filter, 25 Thermopile chip, 26 Infrared sensor self-temperature detection means, 28 Optical path, 30 Light shielding means, 31 Light shielding means cap, 32 Projection Part, 40 anti-magnetic means, 100 pans.

Claims (17)

A top plate formed with a transmission part that transmits infrared rays of at least the first wavelength band;
A heating means that is provided below the top plate and heats an object to be heated placed on the top plate;
An infrared sensor that is provided below the transmission part and has a condenser lens that collects the infrared rays, and detects the amount of infrared rays emitted from the object to be heated;
An optical filter that is provided between the transmission unit and the infrared sensor and transmits the infrared light;
Infrared temperature detection means for detecting the temperature of the object to be heated from the detection value of the infrared sensor;
A control unit for controlling the heating unit based on the detection result of the infrared temperature detection unit;
With
The condenser lens is formed of a silicon substrate,
A transmittance of light in the first wavelength band has a bandpass filter higher than the transmittance in a wavelength band larger than the first wavelength band;
The band-pass filter is composed of a single-layer thin film formed by depositing at least one material of SiO, SiO2, MgF2, ZnS, and Ge on the silicon substrate,
The optical filter is formed of a silicon substrate,
The heating cooker, wherein the transmittance of light in the first wavelength band is higher than the transmittance in a wavelength band larger than the first wavelength band. The top plate is made of crystallized glass,
The transmission part transmits light of 3.0 μm to 4.5 μm as the first wavelength band,
2. The cooking device according to claim 1 , wherein the band-pass filter has a light transmittance of 3.0 μm or more and 4.5 μm or less higher than a transmittance of a wavelength band exceeding 4.5 μm. The optical filter on one or both sides of the plane in which the infrared is transmitted, SiO, SiO2, MgF2, ZnS, and claim 1 or 2, characterized in that it has a thin film formed by at least one material of Ge The heating cooker described in 1. 2. The optical filter has a single-layer thin film formed of any one material of SiO, SiO2, MgF2, ZnS, or Ge only on one surface through which the infrared rays are transmitted. Or the heating cooker of 2 . The thin film, 3.0 [mu] m or more 4.5μm or less of the transmittance of the wavelength band, according to claim 3 or 4, wherein the higher than the transmittance of a wavelength band 15.0μm exceed 4.5μm Cooking device. Between the support means for supporting the heating means and the top plate, a pair of light-shielding means arranged to face each other across the field of view of the infrared sensor,
It said optical filter, heating cooker according to any one of claim 1 to 5, characterized in that attached to the shielding means. Between the supporting means for supporting the heating means and the top plate, a cylindrical light shielding means arranged so as to surround the visual field of the infrared sensor,
It said optical filter, heating cooker according to any one of claim 1 to 5, characterized in that attached to the shielding means. The infrared sensor is disposed below the support means;
The light shielding means has an upper end formed above the upper surface of the heating means,
The cooking device according to claim 6 or 7 , wherein the optical filter is attached to an upper end of the light shielding means. The infrared sensor is disposed below the support means;
The light shielding means has an upper end formed above the upper surface of the heating means,
The cooking device according to claim 6 or 7 , wherein the optical filter is attached to a lower part of the light shielding means. The cooking device according to any one of claims 6 to 9 , wherein the light shielding means is integrally formed with the support means. The optical filter is composed of a polygonal flat plate,
The heating according to any one of claims 6 to 10 , wherein the shading means is formed with a notch corresponding to the shape of the optical filter, and the optical filter is fitted into the notch. Cooking device. The cooking device according to any one of claims 6 to 11 , wherein the optical filter is bonded and fixed to the light shielding means with an epoxy-based or silicon-based adhesive. A position corresponding to the visual field of the infrared sensor is opened, and includes a pressing member that covers at least a part of an upper end of the light shielding unit and a side surface of the light shielding unit opposite to the visual field,
The light shielding means is formed with a protrusion or a groove on the side surface opposite to the visual field of the infrared sensor,
The pressing member is formed with a fitting portion corresponding to the protruding portion or the groove portion,
The fitting portion of the pressing member and the projection or the groove portion of the light shielding means are fitted, and the optical filter is fixed in a state of being sandwiched between the upper end of the light shielding means and the pressing member. The cooking device according to any one of claims 6 to 11 , characterized in that. The optical filter is composed of a flat plate,
The light shielding means is characterized in that a groove corresponding to the thickness of the optical filter is formed on a side surface of the infrared sensor on the visual field side, the optical filter is inserted into the groove, and the optical filter is fixed. The cooking device according to any one of claims 6 to 10 . A sensor case for storing the infrared sensor;
The sensor case is
An opening is formed at a position corresponding to the visual field of the infrared sensor,
Attached to the supporting means for supporting the heating means with a gap,
The cooking device according to any one of claims 1 to 14 , wherein cooling air is passed through the gap. A sensor case that houses the infrared sensor;
A magnetic-shielding means that is made of a non-magnetic metal and disposed between a support means that supports the heating means and the sensor case;
With
The optical filter is disposed in contact with the magnetic shielding means,
The cooking device according to any one of claims 1 to 14 , wherein at least a part of the magnetic shielding means is cooled by cooling air. The sensor case is formed of resin,
The cooking device according to claim 15 or 16 , wherein at least one outer surface of the sensor case is metal-plated.

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